Table 3.
Rheumatoid Arthritis Association With Maternal Farm Experience, Childhood Farm Residence, and Pesticide Use, Sister Study, United States, 2004–2009
| Residential Farm Experience | Case Patients With RA | Noncase Patients | Age Adjusted | Fully Adjusteda | ||||
|---|---|---|---|---|---|---|---|---|
| No. | % | No. | % | OR | 95% CI | OR | 95% CI | |
| Mother lived or worked on farm while pregnantb | 407 | 46,918 | ||||||
| No | 320 | 79 | 38,483 | 82 | 1.0 | Referent | 1.0 | Referent |
| Yes | 87 | 21 | 8,435 | 18 | 1.1 | 0.88, 1.4 | 1.0 | 0.79, 1.3 |
| Lifetime farm residencec | 414 | 47,192 | ||||||
| No farm residence, child or adult | 292 | 74 | 36,255 | 80 | 1.0 | Referent | 1.0 | Referent |
| Childhood only | 84 | 21 | 7,036 | 15 | 1.3 | 1.0, 1.7 | 1.3 | 0.98, 1.6 |
| Any adult | 38 | 9 | 3,910 | 7 | 1.1 | 0.81, 1.6 | 1.1 | 0.75, 1.6 |
| Childhood-only farm residenced | ||||||||
| Pesticides use on crops | ||||||||
| No pesticides used | 30 | 8 | 3,000 | 7 | 1.0 | 0.71, 1.5 | 0.97 | 0.67, 1.4 |
| Used, no personal exposures | 30 | 8 | 2,370 | 5 | 1.4 | 0.99, 2.1 | 1.4 | 0.97, 2.1 |
| Used, with personal exposures | 20 | 5 | 1,235 | 3 | 1.9 | 1.2, 3.1 | 1.8 | 1.1, 2.9 |
| Livestock contact, pesticide use | ||||||||
| No livestock contact | 24 | 6 | 2,094 | 5 | 1.2 | 0.82, 1.9 | 1.2 | 0.74, 1.8 |
| Contact, but no pesticides used | 35 | 9 | 3,314 | 8 | 1.1 | 0.77, 1.6 | 1.1 | 0.74, 1.5 |
| Contact, and pesticides used | 20 | 5 | 1,066 | 2 | 2.1 | 1.3, 3.3 | 2.0 | 1.2, 3.3 |
| Use on livestock and/or cropse | ||||||||
| No livestock (crops only) | ||||||||
| No pesticides used | 14 | 4 | 1,236 | 3 | 1.2 | 0.68, 2.0 | 1.1 | 0.62, 1.9 |
| Pesticides used on crops | 15 | 4 | 1,044 | 2 | 1.7 | 1.0, 2.8 | 1.7 | 0.96, 2.9 |
| Yes, livestock: | ||||||||
| No pesticides used | 13 | 3 | 1,745 | 4 | 0.79 | 0.45, 1.4 | 0.78 | 0.44, 1.4 |
| Pesticides on crops only | 22 | 6 | 1,769 | 4 | 1.4 | 0.92, 2.2 | 1.4 | 0.88, 2.2 |
| Pesticides on crops and animals | 20 | 5 | 1,066 | 2 | 2.0 | 1.3, 3.3 | 2.0 | 1.2, 3.2 |
Abbreviations: CI, confidence intervals; OR, odds ratios; RA, rheumatoid arthritis.
a Models were adjusted for age, race or ethnicity, college education, pack-years of smoking, and childhood socioeconomic status score (numbers are reduced because of missing covariate data on 37 case patients and 3,232 noncase patients).
b Missing data on maternal farm residence for 17 case patients (4%) and 2,001 noncase patients (4%). Percentages are based on nonmissing data.
c Missing responses on 10 case patients (2%) and 1,727 noncase patients (3%) who were eligible but did not complete the farm module. Percentages are based on nonmissing data.
d Excludes those with adult farm residence. Numbers do not always add to total with childhood-only farm residence because of missing values: pesticide use on crops missing for 4 case patients (1%) and 431 noncase patients (1%), livestock contact/pesticide use missing for 5 case patients (1%) and 560 noncase patients (1%). Percentages are based on nonmissing data. Questions about pesticides used on livestock were asked only of women with livestock contact. “No use” included 3% of case patients and noncase patients who reported “don’t know,” and 6% of case patients and 7% of noncase patients who reported no pesticides were applied to animals.
e Includes those with crops only under “no livestock” and livestock only under “livestock,” assuming no livestock contact was equivalent to no pesticide use. Missing responses were assigned to unexposed, no pesticide use categories.